Spatial Resolution

Twin Otter flights were made on 6 tracks that varied in length from 3.04 to 6.5 km. Data were recorded at 32 Hz, at an airspeed of about 55 m/s. The resolution of the original time series was approximately 5 m.

Background color on

Temporal Coverage

Measurements were taken between 15 June and 06 July 2002. Flights were made on the following days: 15, 16, 17, 18, 20, 21, 22, 23, 24, 25, 27, 29 June and 1, 3, 5, 6 July.

Temporal Resolution

Data were recorded at 32 Hz and are provided as averages per flight.

Background color on

Parameter or Variable

The following table describes the column headings in the data table, and the parameters and sensors used.

Column

Type

Units

Description

Sensor

Run

Run number

GMT HR

hour

Greenwich Mean Time at start of run

GMT MIN

minute

Greenwich Mean Time at start of run

GMT SEC

seconds

Greenwich Mean Time at start of run

Duration

seconds

Duration of flight in seconds

DIST

km

Length of run

PALT

run-mean

m

Pressure altitude above mean sea level

Paroscientific 1003D-02 Rosemount 858AJ28 Probe

RALT

run-mean

m

Radio-altimeter height above terrain

Sperry AA-200 Radio Altimeter

TEMP

run-mean

°C

Air temperature

LI-COR C02 Analyzer Temp

DEWPT

run-mean

°C

Dew point temperature

E,G and G Model 137-S10

KT19

run-mean

°C

Radiometric surface temperature

Heitronics KT-19 Pyrometer

GRN

run-mean

Greenness Index (ratio of 730/660 nm reflected radiation)

Skye Industries Greenness sensor

NETRD

run-mean

W/m2

Net radiation from wingtip sensor

Kipp and Zonen CNR-1

CO2

run-mean

ppm

CO2 concentration

LI-COR C02/H20 Analyzer

HDG

run-mean

° true

Aircraft heading

Litton 90-100 IRS, Sperry C-12 Gyro Compass

WIND-dir

run-mean

° true

Wind direction

Rosemount probes

WIND-spd

run-mean

m/s

Wind speed

Rosemount probes

LWN-rms

rms

m/s

rms of wind component from north

LWE-rms

rms

m/s

rms of wind component from east

WEP-rms

rms

m/s

rms of vertical wind component

POT-rms

rms

°C

rms of potential temperature

RC02-rms

rms

mg/kg

rms of CO2 mixing ratio

LI-COR C02/H20 Analyzer

RH20-rms

rms

mg/kg

rms of H2O mixing ratio

LI-COR C02/H20 Analyzer

H

flux

W/m2

Sensible heat flux

LE

flux

W/m2

Latent heat flux

WC

flux

mg/m2/s

CO2 flux

U*

flux

m/s

Friction velocity computed from momentum flux

Ozone Flux

flux

µg/m2/s

Ozone flux, corrected

Scintrex Ozone Analyzer, TECO Ozone Analyzer

Sample Data Record

The following table shows just some of the data columns in the data file:

FLIGHT 01, 15-JUN-02

RUN

GMT HR

GMT MIN

GMT SEC

DURATION

DIST

PALT

RALT

TEMP

DEWPT

KT19

GRN

NETRD

C02

HDG

sec

km

m

m

degC

degC

degC

W/m2

ppm

degT

TRACK

A

2

15

29

32

104

4.93

355

38

22.0

9.9

30.4

1.30

570

373

352

3

15

32

32

87

5.29

354

38

22.0

9.9

30.4

1.33

518

373

179

4

15

36

6

102

5.00

352

36

21.9

10.0

31.2

1.33

569

373

353

5

15

39

3

86

5.34

350

33

21.9

9.9

31.2

1.33

515

373

180

6

15

42

16

103

5.20

349

32

22.0

10.2

31.5

1.38

569

373

353

7

15

45

29

88

5.33

351

34

21.8

9.9

31.9

1.33

523

373

178

Background color on

Software and Tools

Background color on

Data Acquisition and Processing

Derivation Techniques and Algorithms

Processing Steps

Data were acquired by the various sensors on the aircraft and fed into a computer. Processing took place in September 2002 at NRC, employing updated calibrations as well as a Kalman filtering technique that removes small biases in the measured horizontal wind components. For complete information on processing, please refer to the SMACEX Special Report, available in the data directory.

Background color on

Sensor or Instrument Description

Please see the parameter section for a list of the sensors used in the study. The figure below shows where the sensors were placed on the aircraft during SMACEX.